1. Field of Invention
This invention relates to passenger loading bridges, which are self leveling, and a means of preventing the loading bridge floor from contacting and damaging the aircraft door during passenger loading and unloading functions.
2. Prior Art
The Airlines have had a problem with aircraft passenger entrance door damage. The door damage occurs when the door makes contact with the Passenger Loading Bridge (PLB) floor while loading the aircraft. The PLB is equipped with an auto level device that is supposed to keep the floor at a set level in relation to the aircraft. As passengers are boarding or exciting the aircraft, the resulting change in weight causes the aircraft to elevate or lower. Bridge function before apparatus is installed: The existing apparatus has an operate circuit that lets you operate the Horizontal drive, (manually), Vertical drive (manually), Canopy in and out, Cab rotate right and left, Adjustable Cab Floor (ACF) floor up and down. In the Auto level circuit, the arm and wheel are extended out to the aircraft (manually) to detect the aircraft vertical (latitude) position relative to the PLB deck. In the off circuit all functions are cancelled. If the operator fails to set the auto level or if the auto level malfunctions, there is no redundant system to protect the door from making contact with the floor. If this Auto level does not function properly or is disengaged, there is nothing to keep the door from being damaged by contacting the PLB floor. If the PLB is turned off with the off button, all functions are cancelled. At this time, there is no indication the floor is making contact with the aircraft door until it is too late. Consequently, the door is distorted and repair or replacement is necessary. The cost for this service has been as high as $200,000. This is in addition to the time the aircraft is out of service and the time required unloading the aircraft and finding other flights for passengers. Other devices to detect door location have to be manually placed under the door and manually plugged into the wall and only have two functions. These are used with little success. In most cases the gate agent is not trained on where to place the device or where to plug it into the wall or since it is portable, it may not be available for use. Also the gate agent does not have time to figure out the procedure of such a device
Objects and advantages: Our device is stationary and hard wired to the PLB controls needing no set up When activated, it sounds two audible alarms and displays one visual alarm. It retracts and resets the auto level arm automatically. It drives the PLB down away from the aircraft door. If the PLB is turned off with the off button, all functions will occur except for the vertical down alerting the agent that the aircraft door is too close to the PLB door. Our device performs all these functions regardless of which position the selector switch is in (auto level, off, operate). Our device monitors the integrity of the system 24/7. A visual alarm alerts the agent that there is a fault in the system. This device has been demonstrated for several safety personnel at a major International Airport. They expressed great enthusiasm about implementing this on all the PLBs in their system.